1. Field of the Invention
The present invention relates to a machine provided in an engine compartment with an internal combustion engine and a generator driven by the internal combustion engine. The machine is a marine propulsion machine, preferably, an outboard motor.
2. Description of the Related Art
Machines provided in an engine compartment with an internal combustion engine and a generator driven by the engine, such as outboard motors, are disclosed in JP 6-33790 A and JP 59-100093 A.
In a known outboard motor provided with an internal combustion engine and a generator installed in a small volume engine compartment aiming at compact construction, the generator, unlike a flywheel magneto directly coaxially coupled with the crankshaft (output shaft) of the engine, has a housing and is disposed with its shaft separated by a center distance from the crankshaft. When air that has flowed through air inlets formed in the housing into the housing is discharged from the housing as exhaust air, the exhaust air does not easily diffuse far away from the generator because any members that will disturb the exhaust air are not disposed around the generator. Consequently, part of the hot exhaust air, in some cases, flows again through the inlets into the housing so that the cooling efficiency of the generator is reduced.
When combustion air is heated by the hot exhaust air discharged from the generator, the charging efficiency of the internal combustion engine reduces, causing the output of the internal combustion engine to drop. Meanwhile, it is desirable to ventilate the engine compartment at a high air change rate to efficiently cool the internal combustion engine, devices and members installed in the engine compartment.
The present invention has been made under such circumstances and it is therefore an object of the present invention to improve the cooling efficiency of a generator included in a machine provided with an internal combustion engine installed in an engine compartment and disposed in the engine compartment with its shaft spaced a center distance apart from the output shaft of the internal combustion engine. Another object of the present invention to suppress the reduction of the charging efficiency of the internal combustion engine attributable to exhaust air discharged from the generator. A further object of the present invention to improve the cooling efficiency of the internal combustion engine, devices and members covered with an engine cover.